def eratos():
    primes = [True] * (101)
    primes[0], primes[1] = False, False

    for i in range(2, 101):
        if primes[i]:
            for j in range(i*i, 101, i):
                primes[j] = False

    return [x for x in range(101) if primes[x]]

primes = eratos()

a, b = map(int, input().split())

list_primes = []
for p in primes:
    if p >= a and p <= b:
        list_primes.append(p)

if len(list_primes) == 0:
    print(0)
else:
    ans = 0
    for x in list_primes:
        ans += (x**3 - x**2 + x + 1)

    print(ans)